21201023031 has 4 divisors (see below), whose sum is σ = 28268030712. Its totient is φ = 14134015352.

The previous prime is 21201022981. The next prime is 21201023047. The reversal of 21201023031 is 13032010212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21201023031 - 2⁶ = 21201022967 is a prime.

It is a super-2 number, since 2×21201023031² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21201023031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201023131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3533503836 + ... + 3533503841.

It is an arithmetic number, because the mean of its divisors is an integer number (7067007678).

Almost surely, 2^21201023031 is an apocalyptic number.

21201023031 is a deficient number, since it is larger than the sum of its proper divisors (7067007681).

21201023031 is an equidigital number, since it uses as much as digits as its factorization.

21201023031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7067007680.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21201023031 its reverse (13032010212), we get a palindrome (34233033243).

The spelling of 21201023031 in words is "twenty-one billion, two hundred one million, twenty-three thousand, thirty-one".